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With the rear of the car in final primer I spun the car around (Go-Jacks are awesome!) and turned my attention to lining up the doors and front end sheet metal. I'd loosely assembled everything to determine if I'd be able to use the 81 subframe, 70 steering, and 70 core support with the solid body mounts. There are differences in the subframe front horns that affect the position of the bumper brackets and steering but with various modifications it looks like I should be able to get everything to fit.
The door hinges were installed bare metal to bare metal at the factory on the 2nd gen F body cars I've worked on. If the area where the hinge mounts is covered in primers/paint it's a lot more difficult to line up the doors because the paint sticks together when the bolts are snugged or tightened. Then if you try to move a hinge just a little while aligning things it usually jumps farther than you want it to move once you get it to pop free. So I sand down the area on the cowl and door as well as the hinge surfaces to make adjustments easier. Then because I'll be leaving the hinges on the cowl when the doors come off for the cut ins I sanded down the final primer that was already there to 320 for paint because it's easier to sand without the hinges in the way (they'll also get the Scotchbrite scuff before paint). Once sanded, a little spray lithium grease gets shot inside where the plate slides around in the cowl and door and a thin film of grease where the hinge touches the cowl and door. This allows easier adjustment of the doors and a bit of corrosion protection. Careful attention to keep grease off areas that will be painted is a must and after the hinges are mounted wax and grease remover used all around hinges to remove any possible residue. http://i240.photobucket.com/albums/f...pspg0mywq2.jpg http://i240.photobucket.com/albums/f...psurzs3agw.jpg |
I'm currently working on front end assembly/panel alignment and some fender vent aero mods I'll talk about in my next progress post. However I've been wanting to post about this problem unique to 70-73 bird's for years and today's the day!
Soapbox time! 70-73 Firebird front bumper and panel alignment. I was a car guy teen when these cars were new and been researching/studying the bumper mounting , panel fitment, and the gaps for the past 25-30 years since my stepson got his first 70. Most of the 70-73 front ends on birds I see now have not been assembled/aligned correctly. THE FRONT BUMPER IS NOT SUPPOSED TO TOUCH THE FENDERS. There is supposed to be a gap. It's wider than people want to see. Nobody likes it, not even the folks at Pontiac liked it when they were new. As you can see in the pics below the marketing people at Pontiac photoshopped (was that a thing then?) the gap between the fender and bumper right out of some of the pics in the 70 brochure because it looks "funny". I see many beautiful cars where the owners have taken every step they can, buying NOS and correct original pieces for crazy prices just so they know they've got the right stamping's, date codes, etc. only to see the whole front end isn't panel aligned correctly. I feel bad for them because they just don't know. To me it's almost like hearing someone say they've got a "Big Block" Pontiac. Soon after these cars were built they started getting in accidents etc.requiring bodywork and paint. IF the person took it back to the dealer the shop might have put the bumper back on correctly however many shops might just try to eliminate or reduce the gap if they even knew there was supposed to be a gap. It's been over 45 years since these cars were built and so even a body man who was in his 20's is probably retired even if he was a body man his whole life. So the folks who've been repainting these cars the past 30 years or so probably never even saw these cars new and don't realize the bumper isn't supposed to touch the fender. Most in the restoration/ body repair business now never saw these cars before they started being reassembled wrong so they try to split the differences and make the panel alignment/gaps look as good as they can with the bumper tight to the fender because they never even saw one with the correct gap. The misconception has gone on so long now that the majority of the cars I see now are assembled wrong and look kinda wonky but few realize why. The poor panel alignment is often attributed to the lower quality sheet metal stamping of yesteryear. The subframe, bumper brackets, and bumper (as a solidly bolted structure) were isolated from the unibody,fenders, core support, splash pan, and core support/latch brackets (again solidly bolted structure) by 8 rubber bushings allowing the 2 sections to move slightly independent of each other. 4 rubber body mounts, 2 rubber core support mounts, and the 2 rubber upper bumper mounts. This allowed movement of the two structures individually and so a gap was needed between the fenders and bumper to prevent the bumper being deformed on uneven surfaces and when the car was jacked up. When the first urethane bumpers arrived on the 69's they put a rubber gasket between the bumper and body and people didn't like it so in 70 they reduced the gap and left it open. The assembly manual says like up to 3/16" gap but from what I've seen the gap needs to be roughly 3/16" - 1/4" on most of the cars to get everything lined up as well as can be keeping in mind that factory stamping and tolerances of early 70's cars was nothing like today's cars. In this first page from the brochure you can see that the marketing guys made the gap disappear on the passenger side of the upper image while it is clearly seen on the lower image. http://i240.photobucket.com/albums/f...ps53db5f97.jpg On the page below you can clearly see the gap, note the front of the hood lines up with the front of the fender. http://i240.photobucket.com/albums/f...ps200f0ca5.jpg Apparently the marketing folks figured the gap showed up waaay too much on a white car. http://i240.photobucket.com/albums/f...psd6233dc1.jpg Pic below is exaggerated to show how the body lines and fitment get screwed up. Think of it as taking a slice out of a cone and then trying to mate the remaining pieces. The gap needs to be roughly 3/16" - 1/4" on most of the cars to get everything lined up as well as can be keeping in mind that factory stamping and tolerances of early 70's cars was nothing like today's cars. When folks try to have the bumper touch the fender it causes problems aligning the front end sheet metal. Several problems arise and folks try to juggle all the pieces to minimize the affects but the pieces won't line up well so the common thought is "They just didn't make the cars very good back then" These are the most noticeable effects of trying to have the bumper touch the fender. 1. The hood sticking too far back toward the windshield and sticking up even when the hinges are adjusted to the max trying to lower it. 2. The middle of the hood arches above the fender. Commonly attributed to the "Formy arch" or lousy hood springs. It's actually also caused by the hood being too far back and the arch of the hood not matching the arch of the fender. 3. When the bumper is tight to the fender people pull the fenders in toward the hood trying to get the points on the top of the bumper to line up with the top of the fender. this causes too small of a gap to the hood and often the car gets assembled without the side rubber hood bumpers because they push the hood up causing the mid hood arch to be off even more with the fender. 4. When the fenders are pulled in, the bottoms of the fender get pulled in afterward when trying to get the side of the fender to curve like the side of the bumper. Then the splash pan seems like it's too long. 5. The side body line will be off because when pulling the bumper tight to the fender it also gets raised to have the top of the bumper flush with the top of the fender. So the bumper body line ends up slightly higher than the fender body line. Sometimes this gets "fixed" during bodywork with filling/blocking if the bumper is on the car at the time. http://i240.photobucket.com/albums/f...psqlvmwxjp.jpg The crude sketches below show how the car is built. The main portion of the car is comprised of the unibody along with all the front sheet metal bolted solidly together (excluding hood because it's on hinges). It includes the fenders, inner fenders, inner fender extensions, core support, latch support, and splash pan. The smaller section includes the subframe, bumper brackets, and bumper (with lights and grills) bolted solidly together with the front suspension and steering attached. A third section is the engine/transmission bolted solidly together and "floating" on rubber mounts over the subframe. The gap was necessary to allow the two main sections of the car to move a little independent of each other without damaging the sides of the bumper and paint on the leading edge of the fenders.. Even if you use solid body mounts the bumper still needs the gap to get the panel alignment correct because it was designed knowing the gap was necessary and the body lines needed to appear to flow over the gap. http://i240.photobucket.com/albums/f...psd1uncyu6.jpg Came across some pics on another forum that demonstrate how NOT to line up the bumper. This is a classic example of what happens when folks try to have the bumper touch the fender and don't know what they're doing is wrong. As an added bonus it also shows how the more flexible formy hood reacts. Don't worry, I'm not picking on someone's car that's being used like this. It's already apart for restoration. The bumper below looks like it was installed while the car was on jack stands or a lift and they tried to have the bumper touch the fender. Then when they dropped the car on the ground the result was popping the paint on the drivers side of the bumper and a funny gap on the passengers. The hood was moved back so there would be a gap and the hood corners by the windshield probably got sanded off because they looked funny. The fenders were pulled in toward the hood in front trying to match the bumper causing the raised section of the Formy hood mid fender. Also notice the side body line of the bumper is now too high compared to the fender. http://i240.photobucket.com/albums/f...ps2yhvzsnk.jpg [URL=http://s240.photobucket.com/user/NOTATA/media/0321151817_zpsruxsxa1e.jpg.html]http://i240.photobucket.com/albums/f...psruxsxa1e.jpg |
One of the aero changes I wanted to make involves the fender vents. I'm planning on a splitter and pan under the engine compartment. So I need to evacuate the under hood air that comes through the radiator and reduce high pressure air under the hood that causes lift. Many have experienced the effect called "float" at high speeds (over normal highway speed) in regular cars and some models are worse than others. The 2nd gen TA fender vents help reduce that and I want to maximize the benefit.
So I began by doing some tuft testing on the stock vent with the screen removed to see how it performed. Then I made cardboard modifications to the vents and tested again. I spent more than a day on this process testing various configurations and came up with a couple modified vents that should help keep the air pressure lower under the hood. For a more detailed version of the testing and how the modified vents were made see this thread which just covers my aero mods. http://transamcountry.com/community/...?topic=71522.0 The stock TA vent has a hole with surface area about 15 sq. in. The screen in the stock vent blocks off about 5 sq.in. reducing it to 10 sq. in. and creates turbulence as the air tries to exit through it. As I went through the testing process I changed the angle of the leading edge, added wicker bills of varying heights and expanded the opening. The modified vents now have openings about 3 times the sq. in. with steeper leading edge and the design of the housings seem to draw a lot more air from under hood. One set will be used for Land Speed racing type events (less drag) and the one with the wicker at the leading edge will be for road course use (more drag but also more evacuation). As I mentioned it was a long process and lots of variations were tuft tested. Here's a few pics to show a couple of the differences. Stock vent with screen removed. http://i240.photobucket.com/albums/f...psth3q9sas.jpg Modified vent below with steeper leading angle and stock opening. http://i240.photobucket.com/albums/f...ps9hux3vb5.jpg Modified vent with wicker and extra slot opening below. http://i240.photobucket.com/albums/f...psviry1faw.jpg This version seemed to get the best results for evacuation with reduced turbulence. But it wasn't enough "better" to warrant all the extra effort I'd have to put in to incorporate strakes into my design. http://i240.photobucket.com/albums/f...ps4etgb5xy.jpg |
Here are the designs I came up with and made. Will tuft test in the real world once the car is back on track. Top pic below is process. Then stock vent, LSR vent, and track vent.
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Moving along with aerodynamic modifications this is the front end treatment.
The splitter/tray/air dam combination I've got in mind is a bit unusual from those I've seen on other cars. A. Hinged to allow the splitter to be pushed up if I hit corner curbing or something. Splitter could rise till it hits the stock air dam. I've never whacked the stock air dam and I'll probably only loose maybe 1/2" ground clearance. B. Two piece splitter/tray so I can have various splitters that stick out more or less with the biggest reaching out as far as the leading edge of the bumper and out as wide as the wickers on the wheel flares. C. Height adjustable so I can use for street, LSR, Drag strip, road course, or open road with various height air dam extensions. D. Various air dam extensions that will fold up if the splitter gets pushed up. Probably three versions, small for drag race & street , medium for road tracks, and a deep air dam extension with minimal ground clearance for LSR with no splitter but supported from behind by the tray section. E. Breakaway provisions so if something bad happens, damage to the car would be minimal and hopefully confined to the splash pan and stock air dam/wheel flares. F. Cheap/replaceable using as many pieces of scraps left from other projects and junk people gave me as I can. I gathered all the stuff I've been collecting and figured I could make something out of it even if just a prototype. It'll get the scraps out of my way and hopefully save me a few bucks. While today lots of folks use CAD I still use DIG (Draw In Garage) for projects like this. Here's the basic concept drawing. The tray section the various splitters will be attached to has a smaller footprint than the stock air dam/wheel flare section. http://i240.photobucket.com/albums/f...ps8uu4aohi.jpg http://i240.photobucket.com/albums/f...psxpirxxyt.jpg |
Based on my less than artistic freehand quick sketch of what I envisioned I got to making stuff. Below are pics of the splitter/air dam combinations I'll be testing. Not sure if there'll be any issues with using cable supports which might allow the splitter to oscillate or bounce. If there are issues I'll install solid splitter supports.
The contraption in it's current configuration adds about 27 lbs to the nose of the car. This includes a lot of hardware weight I'll eliminate if it works as planned. The splitter easily supports my full weight with just 2 of the cables in place. The hinging ability works and so in theory might save me from wrecking it. Front sections of various lengths can be slid into place in just a couple minutes. I started making plastic pieces to mate the original air dam and wheel flares with the splitter and will finish them when I determine the exact heights I'll try the splitter at once the car is assembled and on the ground with full weight. 3/8" plywood is being used for testing the front sections and I may use a different material later if everything functions as I'd like once road tested. http://i240.photobucket.com/albums/f...psirxstnu6.jpg http://i240.photobucket.com/albums/f...psgsc65mzj.jpg http://i240.photobucket.com/albums/f...psksroqlgy.jpg http://i240.photobucket.com/albums/f...ps91ms5mvr.jpg http://i240.photobucket.com/albums/f...psxyfgvtln.jpg http://i240.photobucket.com/albums/f...psnqctt6dr.jpg |
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Very cool. I like the splitter idea, but I think you will get oscillation with the cable mounts if it doesn't simply get stuck in the up position after a bump gets air under it. From a weight angle, what if you made the final from aluminum, fiberglass or carbon fiber? I think aluminum would be the simplest. With fiberglass being reasonably light, strong, inexpensive and reasonably repairable. I've never worked carbon fiber because I can't make fiberglass pretty enough to show off the weave and never needed that type of weight reduction. |
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http://i240.photobucket.com/albums/f...psr3kuxkxn.jpg |
I love the R&D you're doing, basically a poor man's wind tunnel. Aero is so important and most people don't even know it exists.
You seriously remind me a lot of how I approach things. You're also letting me know I'm not crazy - or at least I'm not alone in my crazy. Hahaha Thanks for sharing. |
Great work and a very nice write up!
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Thanks guys!
Moving on to the front brake duct cooling system.... The Baer brakes are large by huge 14" rotors with 6 piston calipers. The rotors are the curved vane type which are designed to move air from the rotor hat through the hollow vanes in the rotor to cool the rotor as long as it's turning. I want to have additional cooling ducts to aid cooling for several reasons. A. The aero changes I'm making will reduce the air exchange in the wheel wells. So that might contribute to the rotors, pads and calipers heating more than without the aero changes. B. I'm running 285 front tires on 18" X 10" wheels that just barely clear the calipers. So the calipers and rotors are kind of shrouded by the wheels which might reduce cooling. C. With the Yokohama AO 48 DOT R sticky tires I can brake harder during threshold braking before lock up than I would be able to with higher tread wear tires so more heat is generated. D. Keeping the rotors and pads cooler should extend their life. E The car is is stock bodied with no lightweight fiberglass or carbon fiber and propelled by an iron headed Pontiac engine so at 3500 lbs + it's no featherweight race car, yet I'll treat it like one on track. Here's the basics of what I've done. 1. Remove the speed sensor mount to open up more space for a 3" brake duct hose. 2. Make backing plate for the rotor hat that has minimal clearance with a tube to attach the hose. 3. To attach the backing plate I used a threaded boss in the spindle (supplied by Baer with their package) and drilled then tapped two bolt holes in the caliper abutment so the backing plate has three bolts holding it. 4. Modified a couple dashboard vent ducts from mid 80's GM trucks so the 3" brake duct hose would fit on them. They're slightly too big for the duct hose stock so a few V cuts and they can be squeezed just enough to get the hoses on. 5. Mounted the duct opening vents in the core support up high right next to the radiator on each side. This is a high pressure area behind the grills which isn't affected by the bow wave at the very front of the bumper or air dam. I'd originally planned on using the park/turn signal openings however a discussion with Ron Sutton about the bow wave influence and the reduction of pressure on the splitter just below the signal opening caused me to change plans. 6. I've built everything using 3" 300 degree brake duct tubing. It's a tight fit by the outer tie rods and sway bar ends snaking a 3" tube in there with such wide wheels/tires. I checked turning radius, suspension travel considerations, and such but I may find that I need to downsize to 2" tubing. So I'm going to test with the 3" and if all's good make a prettier set of backing plates welded instead of riveted. If there's clearance issues I'll move down to 2" ducts and add inline fans. Here's the pics! Spindle with speed sensor mount in pic below. http://i240.photobucket.com/albums/f...psrjoqy6rx.jpg Speed sensor mount removed (but opposite spindle). http://i240.photobucket.com/albums/f...psnfvxbq5d.jpg White line in pic below shows how much of the rotor hat is blocked by spindle arms, caliper brackets, and abutments. http://i240.photobucket.com/albums/f...ps1aslc5cq.jpg |
I wanted to seal off the openings on the top of the cowl where fresh air enters. This will increase air pressure on the top of the cowl so I'll get more down force in conjunction with a new hood to cowl seal which will be installed after final paint. I decided to use a reproduction screen I already had and modify it to seal off the openings. I used 3/32 EPDM rubber sheet and it's held in place with # 10 - 5/8"Phillips pan head screws and nylock nuts with 3/16" body washers to spread out the clamping force. The higher the air pressure, the tighter the seal will be. The car very rarely ever gets wet so I'm not concerned too much with drainage but if I'm on a trip and it rains I'll just pop the screen out.
Here's the pics! http://i240.photobucket.com/albums/f...psttzxlneu.jpg http://i240.photobucket.com/albums/f...psdymqh7os.jpg http://i240.photobucket.com/albums/f...psaqwvw0ce.jpg http://i240.photobucket.com/albums/f...psebvhimkx.jpg |
Continuing my efforts to manage under hood airflow and pressure I wanted to seal off the inner fender wells above the frame. The stock inner fenders have a factory installed "splash shield" which helps separate the air in the inner fender from the engine compartment. I wanted to take that a step farther. So I made up some patterns and used 1/8" EPDM rubber sheet to more effective seals. I'm going to be running the modified stock upper control arms for a while after reassembly but plan on eventually switching to upper and lower arms that will allow more positive castor and negative camber so I'll need to reconfigure the seals. With that inn mind I'll be using threaded hardware to hold the seals during assembly after paint now but may use pop rivets to save a little weight when the tubular arms are installed.
Stock splash guard in pic below. Note the gaps to the inner fender well not only around the control arm but also where there was no stock shield between frame and inner fender. http://i240.photobucket.com/albums/f...psvv9h3ux2.jpg Pics below show pattern making and the new seals in place. http://i240.photobucket.com/albums/f...pshwsa9axw.jpg http://i240.photobucket.com/albums/f...pszu3fo1iv.jpg http://i240.photobucket.com/albums/f...psdxmtqtsj.jpg http://i240.photobucket.com/albums/f...psgyzwmeqk.jpg |
The inner fender extensions on the 70-73 birds rusted out pretty easily and over the years I've seen a lot of cars missing them completely. It's a part some might just consider part of the crash protection crumple zone or be considered more of a splash guard. However it's also a part that affects aero. Without it the air coming under the front air dam collides with the air in the wheel well and seeks a place to go. I believe that the air will flow through the opening into the area behind the core support.
Twenty five years ago when I first built the car reproductions weren't available and I didn't really have a way to make replacements. I cut off the bottom of one of them because the rust had eaten it all up while the other had rust holes but wasn't as bad. Eventually I got a better (but not great) set off a parts car and planned on installing them.... Ya, never got around to that, and they disappeared along the way. Reproductions are available now, but I have the ability to make them so I did. If it was a customer car I'd have installed repros because of the fabrication labor time, but since it's my car I made them. http://i240.photobucket.com/albums/f...ps1slxm8yg.jpg http://i240.photobucket.com/albums/f...psct2kaqvr.jpg http://i240.photobucket.com/albums/f...pszbemqha6.jpg http://i240.photobucket.com/albums/f...ps2wbwxhca.jpg |
The core support of the early 2nd gen birds had a lot of gaps on the sides and top as well as large openings for the bumper supports to pass through it. I wanted to seal these areas off to keep the air out which should reduce under hood air pressure and increase the difference in pressure in front/back of the radiator which will help the radiator be most efficient.
Now those of you with early 2nd's might go look at the car and think pffft there's only an inch gap here and there and the holes for the bumper supports. However even though they're not directly open to the front of the car the cavity between the core support and the bumper/splash pan is one of (if not the) highest air pressure areas on the car. So the air is trying to get past the core support through the gaps as fast as it can. This is the same principal of why the brake cooling duct openings are placed in the core support rather than on the splash pan. So how big are the gaps really? I added them all up, then recalculated thinking I must be wrong but no.... Imagine a hole this big in the core support letting air in! http://i240.photobucket.com/albums/f...ps0p3djf7f.jpg The bottom of the core support is bolted tight to the lower edge of the splash pan sealing it. So the sides, top, and bumper openings are where I needed seals. To seal the sides and bumper holes I used 3/32 EPDM rubber sheet and pop riveted it in place. 3/16" aluminum rivets with 3/16" body washers. http://i240.photobucket.com/albums/f...psogxtjqrc.jpg http://i240.photobucket.com/albums/f...pslkdr0i3b.jpg http://i240.photobucket.com/albums/f...psfeey0euo.jpg http://i240.photobucket.com/albums/f...ps1zv3uuom.jpg To seal the top of the core support I used the same rubber but with plastic push pin fasteners for a more finished factory look. All of the seals will become tighter as air pressure increases forward of the core support with speed. http://i240.photobucket.com/albums/f...pspdcspzhy.jpg http://i240.photobucket.com/albums/f...ps268td2lo.jpg |
Very nice work and documentation.
I agree with your position on airflow and the core support / radiator. I hear far too many cooling complaints from people who go for the complex and overlook the simple (and sometimes inexpensive) in this arena. Most older cars have terrible aero - especially through the radiator. For years I have argued controlling airflow through the radiator is paramount for proper cooling. Anyone who doesn't agree needs to take a quick look at the OEM's. Any vehicle built in the last 10 or more years has excellent flow through the radiator with little or no traditional grille opening. It's not magic (unless you refuse to understand), it's called science. |
Yup, being in S. FL I hear it regularly. As you said, it's not magic.
On to bringing this thread up to date...... G braces have been around since Herb Adams & his crew were racing 2nd gens back in the early 70's. The basic brace idea itself was/is a good concept which triangulates the front sub frame to the upper cowl. This reduces deflection of the stock sub frame and stiffens up the overall platform so suspension and steering components can do their job better. The Pro-Touring F-Body Gen II adjustable G-braces shown here evolved from the simple early braces and are a great product. They're a very stout design with a nice adjustable feature that allows them to be easily installed on most 2nd gen F body's. The braces are actually much stronger than the cars they're being installed in and that is the focus of this post. By modifying the points where the forces transferred by the G-braces act on the cowl, upper control arm mounting bolt, upper control arm mount, and sub frame we can make the G braces function even better when the car is pushed to it's limits. In my opinion G-braces should only be used on cars with solid body mounts as a minimum, and preferably have sub frame connectors also. Doing any of the modifications discussed in this post without solid body mounts is a waste of time and money (even if you think it looks cool). Additionally, if you're not really pushing the limits of the car at auto-X, hill climbs, or on road race tracks it's doubtful the benefits of most of this additional bracing would be noticed. However I do believe the upper control arm bolt support would be a good addition to any car with any type of G-brace that uses the upper control arm cross shaft mounting bolt as the G-brace lower mounting point. So here's my list of areas that can use a bit of improvement and what I've done. I hope this helps for those who might want to copy what I've done or come up with better ideas. As with most things the evolution will continue. Also for those wondering, Dave at PTFB has been kept in the loop while I was designing/prototyping all these things. You can expect a new bolt on center upper G-brace to cowl support to be available from PTFB very soon (edit: available now). Where the ones shown below only fit low valve cover Pontiac set ups the PTFB one's will fit multiple applications for those with tall covers, LS engines etc. 1. Upper cowl where G-braces attach is three pieces of sheet metal spot welded together. The G brace mounts are almost centered on the large air openings on the top of the cowl which are the weakest areas. Also the drivers side G brace is in the area of the cowl recessed for the windshield wiper motor allowing more flex in that section of the spot welded ledge the brace is mounted to. Improvement 1. A strip of steel plate above and below ledge creating a sandwich and bolted through the pinch welded area. Stiffens the ledge and spreads the force from the brace over a much wider area. Creates a wider thickness for shear forces transferred through the bolts to act on by doubling (or rmore) the thickness of the ledge. Provides a strong section in the center of the cowl ledge where the top of the cowl is stiffer for the additional centered mount triangulation braces I made that do not come with G-braces. The additional braces also provide lateral support. I used bolts but the sandwich plates could be welded in place. 2. Stock upper control arm mount is made of 3/16" steel. It can flex and those of you who've examined them probably noticed that they've deformed over the years a bit around the forward UCA bolt hole from bumping parking blocks, tightening during alignment, or whatever. If your car's apart put a straight edge on the UCA shaft mounting face and you'll see what I'm talking about. The stock UCA bolts were splined for an interference fit. Often on the cars after many years the interference fit has been widened by movement and the splines don't engage tight any more. Improvement 2. Weld a piece of 1/8" flat plate to the face of the UCA mount. Most of us with track cars are already running a bunch of shims on the front and rear UCA shaft bolts to get as much positive castor and negative camber as we can. The 1/8" plate eliminates one shim front/rear and eliminates one surface where things could slip/move.. The 1/8" welded plate increases the thickness of the mount to 5/16 which is a 66% increase and stiffens the mount. Additionally it gives a thicker more solid base for larger splined UCA shaft mounting studs/bolts. 3. The stock UCA shaft bolts are 1/2" with a small splined base. Their intended use was to clamp the UCA shaft to the mount and accept forces applied in compression and tension. They were not intended to receive shear forces trying to wiggle and tip the bolt. With G-braces the shear forces applied by the braces are at roughly 90 degrees to the bolt AND the force is not at the base where the splines are but away the thickness of the shims and control arm shaft so leverage is involved increasing the possibility of tipping or wiggling the bolt. Improvement 3. ARP 1/2" studs with a wide spline base to replace stock UCA shaft bolts. The wide base makes the bolt more stable and spreads force over a bigger area. The spline area is also deeper which combined with the additional thickness provided by the 1/8" plate welded to the mount keeps the bolt more stable. The studs are also longer (cut to length later) allowing shims etc. to run a lot of negative camber and distorted thread locking nuts will be used to prevent loosening. The ARP long studs are stronger and also allow space to utilize an additional support for the stud to transfer force to the frame horns ahead of the UCA mounts. Additional improvement. Adjustable UCA bolt brace between the front UCA bolt/stud and the frame on roughly the same angle as the main tube of the G-brace.. This support transfers loads from the G-brace to the front frame horns reducing the load on the spline section of the UCA bolt by providing additional support on the other side of the G-brace to help prevent tipping or wiggling of the UCA bolt/stud. I feel this is the most beneficial modification and recommend it to anyone using any style of G braces that use the UCA mounting bolt as the lower attachment point. Pic below is an overview showing everything mocked up but not yet fully adjusted and tightened. The sub frame will need to come out for paint after other modifications are done. The bolts and nuts are all serrated flange locking fasteners excluding the ARP studs & grade 8 nuts used for the UCA shaft mount. On the cowl, the top of the G-braces are fastened with 7/16" bolts and the other bolts (including the additional upper braces) are all 3/8". The lower supports for the UCA bolts are fastened to the frame with serrated flange nuts/bolts. Edit: Most of the items shown in this post I've been selling on the TA forums etc. and started a business called Lab-14 to sell them and other products. No website yet but soon. http://i240.photobucket.com/albums/f...psyyvci1im.jpg Pic below shows the 1/8" thick plate welded to the UCA shaft mounting surface. Note the thickness where the splines of the stud will hold the bolt more securely. http://i240.photobucket.com/albums/f...psqaihegpg.jpg Pic below shows the difference between a stock mounting bolt for the UCA shaft and an ARP wheel stud used to replace them. You can see how the wider deeper spline section will support the bolt more rigidly. http://i240.photobucket.com/albums/f...pshozi0tbe.jpg Pic below shows how the additional upper supports are attached to the PTFB Gen II adjustable G-braces and the angle of the lower support that is attached to the UCA bolt and sub frame. http://i240.photobucket.com/albums/f...psqojkvh2v.jpg Pics below show the drivers side lower support. The unused mount on the steering box has to be cut off to provide clearance for the mounting bolt through the frame. Everything's close but fits. Careful marking of where the frame mounting bolt hole needs to be is critical on the drivers side. Passenger side there's plenty of room. http://i240.photobucket.com/albums/f...ps0ropnunl.jpg http://i240.photobucket.com/albums/f...psgrgy5mkp.jpg Pic below shows all the pieces used for the upgrades described that do not come with a set of PTFB Gen II adjustable G-braces. http://i240.photobucket.com/albums/f...psnih6odon.jpg |
With everything mocked up and the last welding done to the sub frame I sandblasted it. Followed the blasting by shooting it with epoxy primer then regular high build primer followed by sanding then gloss black acrylic enamel.
http://i240.photobucket.com/albums/f...psxuklmrhs.jpg http://i240.photobucket.com/albums/f...psakvigpja.jpg http://i240.photobucket.com/albums/f...pshdcbzdyw.jpg http://i240.photobucket.com/albums/f...psibnike74.jpg http://i240.photobucket.com/albums/f...pspn78b2na.jpg |
When I had the roll cage in my car fabricated 7-8 years ago I removed a lot of the interior, took the car to the fab shop where they built the cage, and then I painted the cage and reassembled the interior. I spent a lot of time trying to mask off the dash, headliner, and other interior bits that hadn't been removed so I could spray the cage. I found it extremely difficult (OK impossible) to get everything masked off and try to figure out a way to spray the cage with the windshield and rear window in the car. It just couldn't be done. So I ended up painting the cage with a brush Using PPG DBI (base coat with activator) then sanding the brush marks smooth, then sanding, then painting, then sanding, and painting again until I had several coats on. The DBI is for use without a clear coat. It came out fine overall but it just didn't look the way I envisioned at the start. There were brush marks and other little things I'd notice that bugged me although probably no one else ever noticed with all the roll cage padding etc. in place.
Since I've got everything out of the car except the headliner (bow type), shifter, and some wires this was the time to spray the cage since the dash windows etc. are all out. So I sanded down the previously applied paint and shot it with the same color PPG Deltron Silver Frost base coat followed by PPG Global Matte clearcoat. For those of you who've never painted a cage, it sucks. I don't remember it being any easier when I was 40 years younger and although I'm still slender and agile, a contortionist I am not. However the cage came out the way I wanted it to the first time and I'm happy with the results. http://i240.photobucket.com/albums/f...pscsrxrkno.jpg |
Holy Crap John this car is going to being awesome when it's back together.
I love the detail that you are going to show everything that you are doing. |
Really great work John! Can't wait to see it at the track!!!!
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Thanks guys!
I'm finally nearing the end of bodywork and paint prep. Got the doors in final primer which were the last big parts of the steel body panels and am currently sanding all of the small pieces that are in final primer (about 50) to be ready for sealer/paint. There's lots of different materials used in the construction of all the smaller pieces. Cast metal, stamped steel, various types of plastics, fiberglass, and the Endura bumper. The bumper caused me lots of lost time and materials. The first time I painted the car 25 years ago I used 3M flexible material repair products followed by the old type lacquer primer followed by epoxy primer and top coated with acrylic enamel. Worked great and still looks good on my original bumper. I bought a new (used) bumper about 20 years ago with the intention of modifying when I got around to it, which is during this rebuild. The bumper had several layers of primers and paints over the the original paint. It was all cracked and crappy looking so I blasted and hand sanded it to bare Endura. I modified the bumper by filling the bumper jack slots and trimming the lower lip and then proceeded to use the modern version of the 3M flexible repair material to repair lifting Endura and make it smooth. Then primed with PPG K-38, blocked, primed, and blocked till it was straight with very little primer on it. Then laid a couple medium wet coats of K-38 reduced for final prime and set the bumper aside to allow materials to shrink back while working on other parts. Knowing the bumper was going to get flexed moving it around off the car while working on it I used a flex agent in the primers to slow down full curing. When final primed I put the bumper in a safe place in the house to allow full curing and shrink back.. A year or so later I pulled it out to mock up all the front end sheet metal on the car and the "final" primer was all cracked. I asked at my local paint supply store where I buy all my materials and they had no real positive answer as to why the final prime cracked. I'd gone through the same procedures with lots of other flexible parts for this car as well as modern cars and never had the final prime crack. The only difference was the use of a flex agent. SO, it was time to start from scratch. I stripped off all the primer and repair materials I'd put on the bumper and proceeded to go through the process all over again. Those of you who have sanded Endura bumpers know this is not fun at all because for some weird reason it seems to take twice as long to sand anything on an Endura bumper. This time the bumper was on the car with all the front end sheet metal aligned so I could work it so the panel alignment from bumper to fenders and hood was nice and smooth sanding across the panel gap. I did not use any flex agent in the primers and used PPG Omni primer for the blocking coats to reduce cost a bit then used K-38 reduced for the final prime. It looked perfect, so I set it aside in the house to shrink back and fully cure. I moved on to the G-brace mock up. Several months later I needed to move the bumper out of the house overnight so I stuck it in the garage. In the morning I went to retrieve the bumper and found the cracked primer you see in the pics below. GRRRRRR! So I put the bumper in the truck and zipped up the street to the paint store. They related that a restoration shop they supply was having the same problems on a GTO Endura bumper. A quick internet search showed that others had similar problems when using the modern high fill primers like the PPG Omni and K-38. The general consensus is not to use a high fill but rather an epoxy primer for blocking sanding etc. on Endura. So I sanded all the primer off by hand then sprayed it with PPG DP48LF epoxy primer the paint store guys gave me for free because they felt bad and knew how much time and materials I already had in the bumper. It's now almost ready for "final?" prime with reduced epoxy primer. Apparently the thin Lacquer primer and epoxy primer I used 25 years ago was fine but the Endura bumper expansion/contraction rate is different enough from the rate of the high build primer that it causes the cracking? We'll see...... Tough lesson as I now refer to it as the $3,000.00 bumper because I've got over 100 hours in it plus a couple hundred dollars worth of blasting media, panel bond, flexible repair material, and many coats of primer that ended up on the floor. K-38 is 300 bucks a gallon! So here's the pics. I put some dry guide coat magic dust on the cracks so you can see them in the pics. If it doesn't work out this time I'm gonna buy a fiberglass bumper. Last pic is blocking out the final prime on the shaker scoop, most of the other small pieces are done with blocking and ready for sealer/paint! http://i240.photobucket.com/albums/f...psblamvemk.jpg http://i240.photobucket.com/albums/f...pspm4av833.jpg http://i240.photobucket.com/albums/f...pstwy0kgbo.jpg http://i240.photobucket.com/albums/f...psm1pnok2w.jpg |
I'd blocked out the front fenders for final primer and set them aside when I took the front end sheet metal off to work on the engine/trans and G-brace mock up. I didn't want to mask off everything since the cowl and cage are already painted and the fenders were coming off anyway. Finally got around to shooting the last coat of primer on them today. Will start blocking out the final primer on the major body parts for sealer and paint soon.
Meanwhile I've got all the smaller pieces ready for sealer. With all the extra pieces like the multiple sets of fender vents and rear spoilers I've got about 50 small parts that need to be body color. As if I didn't have enough paint work with body color parts I've also been prepping and painting other parts like the hood hinges, under tray supports, inner fender extensions, etc. http://i240.photobucket.com/albums/f...psyb9kjxt7.jpg http://i240.photobucket.com/albums/f...psrwjiohmo.jpg http://i240.photobucket.com/albums/f...pstkugvfzl.jpg |
Shot some body color on the inside of the fenders today. Then once the paint flashed over I put them in the South Florida natural solar baking area. Will bake them some more tomorrow.
http://i240.photobucket.com/albums/f...psqtgk4my8.jpg http://i240.photobucket.com/albums/f...psx4wbuxvj.jpg I've got a lot of small pieces to be painted body color. Almost ready to start shooting sealer on them. http://i240.photobucket.com/albums/f...pse75bdh2n.jpg |
Wow! Sorry about the paint experience on the endura bumper. I had a similar experience tuning my latest engine combination. Turns out my wideband oxygen sensor was slowly failing and skewing the readings ever so slightly.
Excellent progress, hopefully the bumper saga is over. There is nothing I hate more than chasing my tail. |
So, with this post I'll finally bring this thread up to date. A lot has happened recently so I've got some catching up to do. The short version is listed below with some quick explanations in the paragraphs that follow.
1. Car still in my own self inflicted paint jail. 2. Started a new company called Lab-14 making pieces to repair and/or strengthen structural parts of sub frames and other parts. 3. The 14 Car is now sponsored by PRO-TOURING F-BODY.COM and is getting all new suspension. First, paint jail. I've been working on getting the 50 or so smaller pieces as well as the doors, fenders, trunk etc. into final sealer. Only have the body and hood left to block & seal. There's been no big rush to get everything cut in and assembled for paint because I needed to be able to use the sub frame and related parts for mocking up parts for the new company. Lab-14 (short for Laboratory Fourteen) is my new endeavor. The initial products are low tech, simple things that are used to repair and/or strengthen, the 2nd gen platform. Products for first gens and other platforms will be developed as the company moves forward. Some of the products are items that showed up previously in this thread while others haven't been talked about here yet. I'll write a separate post about the new company and products and go into more detail about the individual parts. PTFB is now sponsoring the car and so all the old suspension components from various manufacturers are being replaced with PTFB GEN II products. The car will remain a traditional coil/leaf spring car (my decision) and will certainly be a challenge to get set up and tuned with the additional down force created by all the aero modifications I've been making. Since I work building cars for others also, I sold everything that came off of my car to a customer with a 70 TA who wanted them all installed. In addition to the springs, sways, control arms, shocks etc. that came off of my car I also installed on the customer car other new pieces from PTFB including an 800 12:1 box, tie rods and adjusters, Idler arm, ball joints including tall uppers, as well as the PTFB solid body mounts and GEN II frame connectors. Well, everyone likes pics, so here's a couple of mine and one of the TA that now sports some of my old parts and a bunch of new PTFB goodies. Digging my way out of paint jail a few pieces at a time. http://i240.photobucket.com/albums/f...pslvvccr9h.jpg Installing Lab-14 front sway bar mounts. Will talk about them in an upcoming post. http://i240.photobucket.com/albums/f...psxi3rfxfe.jpg 70 TA with a new attitude influenced by a lower altitude. You may notice the white ball looking thing on the hood. It's a Samsung 360 degree 3D virtual reality camera. An amazing piece of equipment that's supposed to be available in the USA now. I've had one at my disposal the past several months and it's amazing. If you try one you'll be hooked. I suspect the 360 VR cameras are going to affect video as much or more than Go Pro's did. http://www.samsung.com/us/explore/gear-vr/?cid=ppc- http://i240.photobucket.com/albums/f...pspqzdx90m.jpg |
Great work, John. The car's going to be too nice to race if you're not careful
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Oh no, it'll get raced!
This is my shameless self promotion post about Laboratory Fourteen "Lab-14", a company I started earlier this year. There's no budget for advertising yet so I can't sponsor any of the forums this thread is posted on so if a mod feels this post isn't appropriate or it conflicts with forum rules just delete it and I won't be offended. I'll get back to the regular project posts after this one. As mentioned previously I started a new company named Laboratory Fourteen "Lab-14" based primarily on parts to repair and reinforce the 2nd gen F body sub frame and also including some restoration reproduction pieces. I 'd been making "one of" pieces for repairs and builds on other peoples cars and mentioned the pieces I'd made for my car in this project thread (which is on several forums) asking if anyone else wanted them. After selling through PM's and emails for a while making small batches of products I figured I should just form a legal business and expand the product line. I've owned several successful businesses I built from scratch and operated for as long as 25 years before moving South, so I've got some experience. The concept of Lab-14 is simple products based on repairing and reinforcing factory chassis to provide a solid footing for all the modern suspension and tire technology we have available today. To make this concept work I realized it's gotta be cheaper, easier, and quicker to just buy my products than to try and copy them yourselves. Thanks to all of you who went through PM's and emailing back and forth to purchase products before I finally got the onlne store set up. Here's a link to the store for anyone interested in checking out the products. https://www.lab-14.com/ Most products are for the sub frames and some are G-brace accessories but there's also some restoration sheet metal pieces that have not been reproduced till now. By offering a number of different things that can all be purchased from one place a person can get everything to beef up a sub frame designed to work together from Lab-14 with just one shipping charge. Saves time driving around buying materials and hardware then trying to find items not available locally online. It's easier because the material choices, pattern making, and metal fabrication work is done, plus all the correct hardware has been figured out and included. You can just order everything in one shot from the online store at WWW.lab-14.com rather than trying to make your own stuff buying metal from here or there then fabricating etc.. and figuring out what hardware is needed then purchasing from multiple places. It's cheaper because you're not spending money driving around trying to source materials and hardware, paying shipping from multiple vendors, and buying materials and hardware you don't need because you can only buy in quantities greater than what is actually needed. After all, most people want to just build the car not spend all their time fabricating, sourcing, etc. It takes long enough to complete projects already. Since we all like pics, here's a couple pics of products taken during small batch production to get the company going. http://i240.photobucket.com/albums/f...psghev3d22.jpg http://i240.photobucket.com/albums/f...psgoirbyns.jpg http://i240.photobucket.com/albums/f...ps6zm1rksw.jpg http://i240.photobucket.com/albums/f...psfg34sloa.jpg |
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Cool stuff. I wish you well on your new venture. |
I'll have a few pics for you in the next day or so. Have the underneath stuff installed, with the exception of the sway bar braces. Installing the G-Brace add-ons now.
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Thanks guys!
Doug, I didn't send you instructions for the upper cowl sandwich plates when I sent the others but they should be up on the website by this weekend. |
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http://i240.photobucket.com/albums/f...psxifnihnq.jpg |
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GREAT products you've developed my friend!! Filling a much needed niche for our cars! :cheers: |
John,
I did just what you suspected. Guess I need to decide if I should use another top plate or fix the holes and go back with your original design. On another note, do you know what billet hinges would fit with G-Braces? Doug |
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IIRC we put Fesler hinges in Ty's car and he's got the original G-braces he mentioned in his post above so I'd send him a PM and maybe he can give you a solid answer. |
A serious amount of engineering going on here!
Fantastic job. Thanks for sharing. Tons of valuable info and ideas. Just a great build! |
During the past couple months I haven't worked on the Firebird itself as much as I'd have liked to. I've been busy with the Lab-14 stuff and got involved in replacing the trunk pan, trunk drop offs, inner splash pan, frame rails, and torque boxes in my 67 Camaro that started with the intention of a much smaller project replacing the rear springs. However I did do some deflection testing of the 2nd gen sub frame using various parts from PTFB and Lab-14. I also did some baseline tuft testing on the highway for aerodynamics using a customers car with the same body, ride height etc. as my car (with the owners permission of course).
Pic below was taken during deflection testing. The front foot wells and cowl area were filled with a few hundred lbs of weight while the body was supported on wood cribs. A piece of right angle was bolted to the pinch weld on the body and an indicator bolted to the front of the frame horn to note deflection. Solid body mounts were used and I've boxed the rear body mount area of the subframe. I could get almost 3/4" vertical deflection of the sub frame alone when using a floor jack to apply pressure straight up under the frame horns until the body started to lift off the wood cribs. Not sure if more weight in the body would allow even more deflection but I was surprised to see how much frame deflection there was. I would expect similar deflection in the opposite direction would be possible and may test for that when I do some torsional testing. With a combination of the PTFB G-braces and Lab-14 parts vertical deflection was reduced to less than 1/8 " which appeared to be caused by the deflection of the floor pan where the rear body mounts on the sub frame attach under the front seats. http://i240.photobucket.com/albums/f...psjgrgdr4x.jpg The availability of a car with the same body, ride height, and tire size as a baseline test mule prompted me to do some tuft testing at highway speeds to get a good look at whats going on with the stock body configuration I started this project with. I'll do similar testing after my car's back on the road to see if I can note any differences due to all the aero changes and modifications. I'll post a couple still pics here and if anyone's interested there's some 360 degree VR videos we made I'll put links for . Those with certain phones or other devices may be able to pan around 360 but you'll need a headset to see full 360 3D VR. Sound is mostly wind noise since the 360 camera was out on a stick held out the window at 60-70 MPH so just turn it down. https://www.youtube.com/watch?v=6KQA9BzpN50 https://www.youtube.com/watch?v=h6pxo5eh7Zw By being able to put the videos up on the big screen with the projector I can watch small areas or even individual tufts. So for those who always wondered if there is a ram air effect influencing the air for a 2nd gen TA shaker scoop created by the high pressure area at the base of the windshield, the answer is no at up to 70 MPH. I'll test that again with my own car at much higher speeds on track but I doubt there will be any noticeable air being forced into the scoop. If anything there's a possibility air may actually be getting pulled out at high speeds. http://i240.photobucket.com/albums/f...pslrtvi7sc.jpg http://i240.photobucket.com/albums/f...psfunvhaet.jpg http://i240.photobucket.com/albums/f...pscm1tawj2.jpg |
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